In the commonly assigned, copending application entitled High Voltage Power Supply Particularly Adapted for a TWT, Ser. No. 909,439, filed Sept. 19, 1986, of which I am a coinventor, there is disclosed a relatively soft high voltage power supply for cathode, collector and helix electrodes of a traveling wave tube (TWT). The prior art circuit includes a low voltage transformer and four switching field effect transistors (FET's) arranged in a bridge network. Current from the bridge network flows via a series resonant circuit to plural, stacked voltage multiplier circuits. Each of the voltage multiplier circuits is transformer coupled to the resonant circuit via a separate toroidal core transformer.
Each of the voltage multiplier circuits includes plural, inexpensive, high speed switching signal diodes, typically having a recovery time of 3-4 nanoseconds so they are capable of responding to and rectifying relatively high frequency currents, i.e., frequencies greater than 300 KHz. The fast recovery time of the switching diodes is a very small fraction of a half cycle of the resonant frequency currents.
The prior art circuit is particularly well suited to power traveling wave tubes having cathode to collector voltages in the 10 KV range and power requirements in the 2 kilowatt range. Many traveling wave tubes have significantly lower voltage and power requirements. The power supply requirements of such tubes are advantageously satisfied with structures having lower space, volume, cost and component count requirements. In particular, it would be advantageous to eliminate the need for the low voltage power transformer and all but one of the switches of the FET bridge circuit. It would also be advantageous to eliminate any type of magnetic coupling transformer.
It is, accordingly, an object of the present invention to provide a new and improved relatively inexpensive DC power supply particularly adapted for traveling wave tubes having relatively low voltage and power requirements.
Another object of the invention is to provide a new and improved relatively inexpensive high voltage DC power supply particularly adapted for the cathode, helix and collector electrodes of a traveling wave tube, which power supply has low volume, weight and component count requirements.
A further object of the invention is to provide a new and improved relatively inexpensive high voltage DC power supply responsive to a low voltage DC source that is chopped by a single transistor switch for supplying resonant current to an AC to DC converter via capacitive coupling circuits, to eliminate the need for a low voltage transformer.
A further object of the invention is to provide a new and improved high voltage DC power supply employing stacked voltage multiplier circuits having inexpensive switching diodes responsive to relatively high frequency currents derived from a resonant circuit.